Try -
$("#column_select").change(function () {
$("#layout_select").children('option').hide();
$("#layout_select").children("option[value^=" + $(this).val() + "]").show()
})
If you were going to use this solution you'd need to hide all of the elements apart from the one with the 'none' value in your document.ready function -
$(document).ready(function() {
$("#layout_select").children('option:gt(0)').hide();
$("#column_select").change(function() {
$("#layout_select").children('option').hide();
$("#layout_select").children("option[value^=" + $(this).val() + "]").show()
})
})
Demo - http://jsfiddle.net/Mxkfr/2
EDIT
I might have got a bit carried away with this, but here's a further example that uses a cache of the original select list options to ensure that the 'layout_select' list is completely reset/cleared (including the 'none' option) after the 'column_select' list is changed -
$(document).ready(function() {
var optarray = $("#layout_select").children('option').map(function() {
return {
"value": this.value,
"option": "<option value='" + this.value + "'>" + this.text + "</option>"
}
})
$("#column_select").change(function() {
$("#layout_select").children('option').remove();
var addoptarr = [];
for (i = 0; i < optarray.length; i++) {
if (optarray[i].value.indexOf($(this).val()) > -1) {
addoptarr.push(optarray[i].option);
}
}
$("#layout_select").html(addoptarr.join(''))
}).change();
})
Demo - http://jsfiddle.net/N7Xpb/1/